This invention relates to aircraft ejection seat systems.
An aircraft ejection seat system is known in operation of which, following the ejection of the airman/seat combination from the aircraft, one or more drogue parachutes are first deployed, which ultimately bring about deployment of a main parachute with which the drogues are connected by a line, a predetermined delay between deployment of the drogue parachute or parachutes and the deployment of the main parachute being, however, ensured by arranging that the line connected with the drogue parachutes is initially connected fixedly with the ejection seat via a shackle, a time delay device associated with said shackle being arranged to allow the latter to open after a predetermined period to effect deployment of the main parachute. The purpose of this delay before allowing deployment of the main parachute is to allow the drogue parachutes, in the event that the ejection takes place while the aircraft is travelling at high speed, to slow the ejection seat/airman combination down sufficiently, before deployment of the main parachute, to prevent damage to the main parachute or the airman, which damage might otherwise occur through deployment of the main parachute at an excessive air speed. In one known arrangement, the delay before deployment of the main parachute is of the order of 11/2 seconds.
The delay in deployment of the main parachute is, of course, unnecessary if ejection takes place while the aircraft is travelling at low speed, and if the aircraft is also relatively close to the ground, such delay may also be positively undesirable.